Association between flower stalk elongation, an Arabidopsis developmental trait, and the subcellular location and movement dynamics of the viral non-structural protein P3.

[EN] Virus infections affect plant developmental traits but this aspect of the interaction has not been extensively studied so far. Two strains ofTurnip mosaic virusdifferentially affectArabidopsisdevelopment, especially flower stalk elongation, which allowed phenotypical, cellular, and molecular characterization of the viral determinant, the P3 protein. Transiently expressed wild-type green fluorescent protein-tagged P3 proteins of both strains and selected mutants of them revealed important differences in their behaviour as endoplasmic reticulum (ER)-associated peripheral proteins flowing along the reticulum, forming punctate accumulations. Three-dimensional (3D) model structures of all expressed P3 proteins were computationally constructed through I-TASSER protein structure predictions, which were used to compute protein surfaces and map electrostatic potentials to characterize the effect of amino acid changes on features related to protein interactions and to phenotypical and subcellular results. The amino acid at position 279 was the main determinant affecting stalk development. It also determined the speed of ER-flow of the expressed proteins and their final location. A marked change in the protein surface electrostatic potential correlated with changes in subcellular location. One single amino acid in the P3 viral protein determines all the analysed differential characteristics between strains differentially affecting flower stalk development. A model proposing a role of the protein in the intracellular movement of the viral replication complex, in association with the viral 6K2 protein, is proposed. The type of association between both viral proteins could differ between the strains.This work was funded by several INIA grants. Silvia Lopez-Gonzalez was funded by a predoctoral FPI-INIA fellowship/contract. P.S. was the recipient of an EU fellowship from an EU-India bilateral agreement (BRAVE Program). We thank Professor John Walsh (Warwick University, UK) for his generous gift of virus isolates. The great technical assistance of Lucia Zurita is also acknowledged. We thank the Spanish Ministry of Science for the Severo Ochoa Excellence Accreditations to the CBGP (SEV-2016-0672).López-González, S.; Navarro Bohigues, JA.; Pacios, LF.; Sardaru, P.; Pallás Benet, V.; Sánchez, F.; Ponz, F. (2020). Association between flower stalk elongation, an Arabidopsis developmental trait, and the subcellular location and movement dynamics of the viral non-structural protein P3. Molecular Plant Pathology. 21(10):1271-1286. https://doi.org/10.1111/mpp.1297612711286211